A display monitor is an important element of a general-purpose computer system, and accounts for a significant portion of the total cost of a system. The display monitor is the systems's principle user interface, and functions to provide information to a user in both graphic and text form.
Manufacturers of monitors are motivated to improve their products by improving characteristics such as resolution, contrast, and clarity. Over time, significant improvements have been made, but not without problems and expense.
The need to provide improved functionality in monitors has made state-of-the-art monitors complex devices, and in many instances the most expensive component of an overall computer system. For example, many monitors are provided with on-board, microprocessor-based controllers, including control routines for relatively complex operations like power management.
Conventional monitors typically have built-in control inputs for such things as brightness, contrast, picture position and sizing. These control inputs are typically rotary potentiometers, and may be mounted at different locations around the case of the monitor as determined by each manufacturer. They may be located on the front in plane with the display screen, on the side, in the back, or on top of the case, often behind a small panel a user may open to access the controls. Moreover, the controls for brightness and contrast may be located on a separate area of the case than positioning and sizing controls. Also, such controls may be digital or analog in design. There are few, if any, industry standards that dictate a user interface for such controls on monitors, and therefore there is a wide variety of locations and types of control input for such monitors.
In a cathode ray tube (CRT) monitor, the control inputs for contrast and brightness typically interact with video circuitry in the monitor, and modulate the signal by varying electrical potential to one or more control grids that effect the emissions from a cathode filament. The brightness control, for example, adjusts the level of the scanning electron beam, which in turn makes the on-screen images brighter or less bright. Contrast is the linear relationship between incoming video dot data signal strength 47 and the current screen brightness.
Besides brightness and contrast control inputs, there are also typically control inputs for position and sizing, which allow a user to alter the position of the display on the screen to some extent, and to adjust the height and width of the display area on the screen.
The control inputs described above must be accessed under several different circumstances. For example, at different times of day, and at night, the ambient light conditions may vary, requiring an adjustment in brightness. Moreover, brightness and contrast are typically somewhat interactive, so when one is adjusted it is usually expedient to adjust the other.
Making control inputs as described requires a user to reach to the monitor, sometimes to different locations around its case, to find the proper control. Moreover, the control inputs do not show adjustment limits or the present position or percentage of input.
What is clearly needed is an easier, more convenient method with suitable apparatus for adjusting display characteristics for a display monitor without having to access control input devices on the monitor. The new apparatus and method should provide for input at conventional input devices and transmit control settings and variances for adjusting display characteristics without requiring new apparatus at the host or in conventional connections between the host and the display.